Chris Hogg posted
Because (the greenies say) it will reduce the total output of undesirable waste products like CO2 and spent nuclear fuel. The argument being that you don't have to use the non-renewable energy sources while the wind *is* blowing, even if it doesn't blow all the time.
Depends on what you mean by "a little". There are times the output from all of them is zero (rare), plenty of times when its under 5%. Taken across the year the load factor is somewhere between 25% and 30%
With enough dispatchable CCGT generating capacity we could probably balance the grid with perhaps 50% more notional installed capacity than we currently have. Any more capacity than that would be pointless really.
With what we currently have, they could in theory reach about 25% of demand - depending on time of day / year.
You can't even count on that. There are times where "no wind" means none at all (at least capable of generating). So you will always need 100% of demand as backup capacity.
Perhaps we need mobile turbines ;-)
That argument would be fine, if the amount of wind-generated electricity resulted in an equivalent amount of coal-fired generation being switched off with the reduction in CO2 that that would save. But it doesn't, because coal-fired power stations have to be kept up and running on standby to enable them rapidly to be brought back on line when the wind drops. It's known as 'hot spinning'. I'm not sure of the relative amounts of CO2 produced by a power station on standby compared with when running on full power, but it's somewhere around
50%, I believe. Perhaps someone can give me the correct figure. Etherington says the CO2 saving is between 30 and 50% of the equivalent installed wind capacity.But France produces very little CO2 in its electricity generation, simply because most of it comes from nuclear. If we had more nuclear plants, we would cut our CO2 emissions, and wouldn't need wind generators.
And it's becoming increasingly questionable whether global warming is happening. If it's not, then CO2 emissions are irrelevant anyway.
Its a fair point in theory, but the practicalities make it very difficult in real life.
Nuclear and coal can't be modulated quickly enough to balance the variability of the wind (and there is not much point trying to save nuclear fuel anyway since its a negligible part of the cost of running the plant). So all wind is really doing is displacing gas.
The way it has been implemented (more importantly the say the subsidies work), its non economic not to use the wind power when it is available. Thus pushing gas generation off the grid. This sounds like a "good thing" at a superficial level, but the implication is that you may well be forcing generators off the grid at the time when they are going to generate most of their income. So it then becomes no profitable to build and operate gas plant.
Google "spinning reserve" to see how dumb that argument is.
Chris Hogg posted
Is it not feasible to "turn down" a gas-fired power station so that you run it at slightly below capacity when the wind is blowing, and then turn it up again when the wind drops? Do they really have to be either
100% on or on standby with nothing in between?Well, yes, but if you accept that nuclear is the way to go then the whole renewable thing is moot anyway.
Wouldn;t that depend on where the wind was, wind is rarely constant. (unless you have a cider and kebab supper).
even in an hour it can change wquite a bit up and down the contry and it's not easily predicatable in a short time. Although there are p[lans for a £97m computer upgrade.
Wind-powered with sails?
I wonder how many wind turbines it takes to power a £97M computer?
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Are you missing my point? What I was getting at was "Based on ongoing experience of how little a contribution wind can sometimes make, (hypothetically) how many wind turbines would it take to have a fair chance of meeting our full-load demand?" I'm know this is not a realistic goal, but it might show up how totally inadequate wind could be if it's all we had.
Compressed air storage, (with or without liquification and heat recovery).
Electrical generation used on site for electrolysing water to produce and store hydrogen.
Atmospheric carbon sequestration to produce synthetic hydrocarbon fuels.
Mostly all hideously expensive and / or inefficient...
Yup getting away from the need to consume and generate in lock step symphony would open up loads of options.
What's a fair chance? One day per year without electricity a year or more?
At a rough guesstimate a million 1 megawatt (the 60 metre ones)turbines would probably supply enough electricity for all but about 30 days a year.
AIUI it happens all the time; that's how they balance supply and demand on the grid ATM, within certain limits, until they reach a point when they can disconnect a generating unit completely or add one in, as necessary. But the key question is whether running a generator at 90% generating capacity actually saves 10% of the fuel and only produces 90% of the CO2. I don't know, but I have the impression that it's not that simple, and that you actually only save between 3 and 5% of the fuel.
TNP probably knows, but he doesn't seem to be around ATM.
Quite. So build nuclear.
Yup!
Well, brown coal *with* FGDS, and weren't they looking at CCS too?
And so far I've not seen a single response from the likes of Adrian, Dave Plowman, or harry to suggest a viable alternative. Their approach appears to be that renewable is good so we should build it, end of.
In message , Ian Jackson writes
I thought it had been made blatantly obvious several times over just how inadequate wind is as a source of electrical energy for the national grid. I've nothing against individuals using wind for their own personal use except that I strongly object to me subsidising what one farmer claimed recently was a "reasonable" return of 16%+ return on his investment.
I would hope that FGDS would be mandatory. CCS always seems to be just around the corner, although I see there are actually quite a lot of places using it, mainly oil fields to enhance oil recovery, see
PS: if you want to know more about the (in)efficiency of wind farms, read Etherington's book 'The Wind Farm Scam'. I believe it's out of print, but S/H copies available at reasonable prices. See
I guess you mean the new plants but that's still an awful lot of fossil CO2 being shoved into the atmosphere that the switched off nukes wouldn't have done.
Do the old coal plants have FGDS?
There seem to have been quite a few goes at CCS an quite a few have not survived...
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